View source for M-325

{{Short description|American cryptography machine}}
{{Infobox computer hardware
| name         = M-325
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| image        = [[Image:Sigfoy2004a-1.jpg|280px|]]
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| caption      = The M-325 (SIGFOY) cipher machine was inspired by the German [[Enigma (machine)|Enigma]]
| invent-date  = 1944<ref name="Bauer2013">{{cite book|author=F.L. Bauer|title=Decrypted Secrets: Methods and Maxims of Cryptology|url=https://books.google.com/books?id=E-epCAAAQBAJ&pg=PA133|date=9 March 2013|publisher=Springer Science & Business Media|isbn=978-3-662-03452-1|pages=133–}}</ref>
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| type         =rotor machine
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In the [[history of cryptography]], '''M-325''', also known as '''SIGFOY''',<ref name="Bauer2002">{{cite book|author=Friedrich Ludwig Bauer|title=Decrypted Secrets: Methods and Maxims of Cryptology|url=https://books.google.com/books?id=s9y9p2jP6pQC&pg=PA137|year=2002|publisher=Springer Science & Business Media|isbn=978-3-540-42674-5|pages=137–}}</ref> was an American [[rotor machine]] designed by [[William F. Friedman]] and built in 1944.<ref name="LeeuwBergstra2007">{{cite book|author1=Karl Maria Michael de Leeuw|author2=Jan Bergstra|title=The History of Information Security: A Comprehensive Handbook|url=https://books.google.com/books?id=pQBrsonDp6cC&pg=PA407|date=28 August 2007|publisher=Elsevier|isbn=978-0-08-055058-9|pages=407–}}</ref> Between 1944 and 1946, more than 1,100 machines were deployed within the [[United States Foreign Service]]. Its use was discontinued in 1946 because of faults in operation. Friedman applied for a patent on the M-325 on 11 August 1944;<ref name="Bauer2006">{{cite book|author=Friedrich L. Bauer|title=Decrypted Secrets: Methods and Maxims of Cryptology|url=https://books.google.com/books?id=hfWTDr_bvMwC&pg=PA151|date=24 November 2006|publisher=Springer Science & Business Media|isbn=978-3-540-48121-8|pages=151–}}</ref> it was and was granted on 17 March 1959 (US patent #2,877,565).

Like the [[Enigma machine|Enigma]], the M-325 contains three intermediate rotors and a reflecting rotor.

[[Image:M-325.png|right|thumbnail|280px|Friedman patented the design of the M-325 in US patent #2,877,565.]]

==See also==
* [[Hebern rotor machine]]
* [[SIGABA]]

==References==
{{reflist}}

==Further reading==
* Louis Kruh, Converter M-325(T), ''Cryptologia 1'', 1977, pp143&ndash;149.

==External links==
* [https://web.archive.org/web/20061016162123/http://www.ilord.com/m-325-manual.html Operating and Keying Instructions for Converter M-325(T) Headquarters], Army Security Agency, July 1948, scanned and transcribed by Bob Lord.
* [http://www.jproc.ca/crypto/m325.html Friedman M-325] &mdash; information and photographs.
* {{US patent|2877565}}

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[[Category:Rotor machines]]
[[Category:Cryptographic hardware]]
[[Category:World War II American electronics]]